1 /*
2  * Copyright (C) 2013 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.android.accessorydisplay.common;
18 
19 /**
20  * Defines message types.
21  */
22 public class Protocol {
23     // Message header.
24     //   0: service id (16 bits)
25     //   2: what (16 bits)
26     //   4: content size (32 bits)
27     //   8: ... content follows ...
28     static final int HEADER_SIZE = 8;
29 
30     // Maximum size of a message envelope including the header and contents.
31     static final int MAX_ENVELOPE_SIZE = 64 * 1024;
32 
33     /**
34      * Maximum message content size.
35      */
36     public static final int MAX_CONTENT_SIZE = MAX_ENVELOPE_SIZE - HEADER_SIZE;
37 
38     public static final class DisplaySinkService {
DisplaySinkService()39         private DisplaySinkService() { }
40 
41         public static final int ID = 1;
42 
43         // Query sink capabilities.
44         // Replies with sink available or not available.
45         public static final int MSG_QUERY = 1;
46 
47         // Send MPEG2-TS H.264 encoded content.
48         public static final int MSG_CONTENT = 2;
49     }
50 
51     public static final class DisplaySourceService {
DisplaySourceService()52         private DisplaySourceService() { }
53 
54         public static final int ID = 2;
55 
56         // Sink is now available for use.
57         //   0: width (32 bits)
58         //   4: height (32 bits)
59         //   8: density dpi (32 bits)
60         public static final int MSG_SINK_AVAILABLE = 1;
61 
62         // Sink is no longer available for use.
63         public static final int MSG_SINK_NOT_AVAILABLE = 2;
64     }
65 }
66